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Differences with other machinesPermanent magnets make it possible to• use smaller pole pitches• use fractional pitch concentrated windings• use larger air gaps• position with higher accuracy Challenge the future 18

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Advantages and disadvantagesAdvantages of PM machines compared to alternatives:• more efficient• higher power density• higher accuracies• high speedsDisadvantages• limited field weakening• risk of demagnetisation• cost? Challenge the future 19

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Structure1 Permanent magnets2 Classification of PM machines3 What is different from other types of machines4 Calculation methods5 Issues6 Conclusions Challenge the future 20